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Tuesday, November 15, 2011. Bellringer If you have paperwork to turn in, please leave it on your desk. I will get it. Copy the “I can” statement from the board. Fill out your agenda. Remember CHAMPs expectations!. CHAMPs C: 0 (when the bell rings)
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Tuesday, November 15, 2011 Bellringer • If you have paperwork to turn in, please leave it on your desk. I will get it. • Copy the “I can” statement from the board. • Fill out your agenda. • Remember CHAMPs expectations! CHAMPs C: 0 (when the bell rings) H: quietly ask a neighbor; after bell, raise hand A: independent work M: 0 (after bell rings) P: silently completing bellringer
Balanced and Unbalanced Forces Introduction to Unit 3 – Forces and Motion
Forces and Motion Notes Passing Lane Notes • Key Idea • Detail • Detail • Key Idea • Detail • Detail
What is a force? • A force is a push or pull that causes an object to move, stop, or change direction
What is a force? A. A push B. A pull C. Anything that causes a change in motion D. All of the above
Force • Forces come in pairs • Forces have a magnitude and a direction Magnitude: 5N Direction: north (up) 5N, north (up)
Forces can be represented by arrows. • The size of the arrow represents the magnitude and the point shows its direction.
Forces always exist in pairs. • True • False
What units are used to measure forces? • A. Grams • B. Meters per second • C. Newtons • D. Arrows
What symbol is used in diagrams to indicate a force? • A star • An arrow • A dotted line • The letter “F”
NET FORCE • When all forces are combined together it is called the net force. • Forces in the same direction combine by addition. • Forces in opposite directions combine by subtraction.
Wednesday, November 16, 2011 Bellringer • If you have paperwork to turn in, please leave it on your desk. I will get it. • Copy the “I can” statement from the board. • Fill out your agenda. • Remember CHAMPs expectations! CHAMPs C: 0 (when the bell rings) H: quietly ask a neighbor; after bell, raise hand A: independent work M: 0 (after bell rings) P: silently completing bellringer
Balanced and Unbalanced Forces • Forces occur in pairs and they can be either balanced or unbalanced
Balanced Forces • Balanced forces do not cause change in motion • Net Forces=0 • They are equal in size and opposite in direction
Group Question • Draw a Balanced Seesaw Showing Forces
Unbalanced Forces • An unbalanced force always causes a change in motion. • When unbalanced forces act in opposite directions you can find the net force • Net force • Magnitude • The difference between the two forces • Direction • Direction of the largest force
Unbalanced Forces 3 N, right 6 N, left = 3N, left
Unbalanced Forces 4 N, left 10 N, right = 6N, right
Unbalanced Forces 5 N, right + 10 N, right = 15N, right
Group Question 2 Draw An Unbalanced Seesaw Showing Forces
Two tugboats are moving a barge. Tugboat A exerts a force of 3000 newtons on the barge. Tugboat B exerts a force of 5000 newtons in the same direction. What is the combined force on the barge? A. 2000 Newtons B. 5000 Newtons C. 3000 Newtons D. 8000 Newtons
Group Question 3 Draw arrows showing the individual and combined forces of the tugboats.
Suppose that Tugboat A exerts a force of 2000 newtons on the barge and Tugboat B exerts a force of 4000 newtons in the opposite direction. What is the combined force on the barge? A. 2000 Newtons B. 4000 Newtons C. 6000 Newtons D. 8000 Newtons
Group Question 4 • Draw arrows showing the individual and combined forces of the tugboats
Could there ever be a case when Tugboat A and Tugboat B are both exerting a force on the barge but the barge doesn’t move? A. Yes B. No
A Quick Recap • Forces are a PUSH or PULL • Unbalanced Forces cause a change in motion. • No motion occurs when forces are balanced. • Forces are measure in NEWTONS. • Forces are represented by arrows. • The overall force is called the NET FORCE
Forces and Motion Notes Passing Lane Write 3 questions that can be answered using today’snotes. (*Place the questions next to the key ideas.) Notes • Key Idea • Detail • Detail • Key Idea • Detail • Detail
Ender • Gauge your understanding of today’s “I can” statement. (Check the line.) • On the lines underneath, prove the “I can” statement. (In other words, explain the difference between balanced and unbalanced forces.)